In the related art, a self-registration system is known as a system that can simplify a purchase transaction. In the self-registration system, a customer launches a self-registration program on a hand-held computing device and registers data of commodities to be purchased through the computing device. As the data registered are transmitted to a point-of-sale (POS) terminal, a process required to complete the transaction at the POS terminal can be simplified.
In the related art, an electronic receipt system is also known as a system that can digitalize contents of a purchase transaction. In the electronic receipt system, a customer launches an electronic receipt program on a computing device and sends a request for electronic receipts related to purchase transactions made by the customer.
Usually, for each of the above computer-based commerce systems, a customer needs a customer (user) ID to log into the system and an authentication process of the system is separately established. It would be desirable if a plurality of computer-based commerce systems can be used in a single purchase transaction in a more convenient manner.